Voltage Regulator !

[jleaman]

Has any one built the nelson pass Voltage regulator's. ? Im thinking about bulding two of them 1 per amplifier i have 2 1kva toroidal transformers 35-0-35 and would use a regulator to bring it down to 15-0-15 V Any one have any idea's or what they used ?

[Stocker]

Certainly loads of them have been built.

Why would you rather burn off all that energy as heat instead of unwinding or rewinding the transformer? This seems like a bad idea, unless you live in a VERY cold climate.

[paulb]

Are the transformers identical? If so, you could wire the primaries in series and use the secondaries, one for each of a stereo amplifier. The load on each transformer has to be the same.
Or you could parallel the secondaries, using low value resistors in series to help share the load.
I agree with the previous caller, that's a LOT of heat to waste. However, I'd be leery of unwinding the secondaries. Sounds like a lot of work.

[jleaman]

I could look at the transformer and see if it has dual primarys and see if i can change it.. if so ill do that. if not then maybe i should just sell them. BUT having a regulated psu would be better

[planet10]

Given that it is for a class A amplifier, you could also do a choke input filter... this would give you a raw DC of about 30V after diode drop, and more current delivery... still a lot of juice to burn off... this might be best done with a shunt reg.

dave

[jleaman]

I could do that but i need to get it down to 15V so 15-0-15

35-0-35 ac is 40-0-40 35vac * 1.41 = 39.9 rounded ^ 40V rails - 15 = 25V that i need to remove

[xplod1236]

Originally posted by jleaman
35-0-35 ac is 40-0-40 35vac * 1.41 = 39.9 rounded ^ 40V rails - 15 = 25V that i need to remove

no. 35-0-35 vac is +/-50 vdc, so that's 35v you need to remove

[jleaman]

Originally posted by xplod1236


no. 35-0-35 vac is +/-50 vdc, so that's 35v you need to remove

heh i'll re-type this..




35-0-35 ac is 50-0-50 35vac * 1.41 = 49.9 rounded ^ 50V rails - 15 = 35V that i need to remove

[jleaman]

Brain fart..


This transformer is..

2 blue wires measure 35v AC
2 brown wires measure 35v Ac
one green one. I presume GND
a set of white and black ac in.

on the blue / brown set they both have one wire that has a shield plastic on it. I wonder if i just use one set of blue wires / brown and use that as the ac in on the boards i could split 35v in half and get 17V i could use that for my aleph mini's could i parallel the Secondary.. ?

Maybe i should post a picture of what I’m talking about ?

[Stocker]

If that one wire with a plastic shield is a center-tap, then it could be (roughly) 17-0-17 which is much more reasonable for regulating to +/-15. If not, it really is not all that much work to unwind a toroid...usually